1. Technical Field
The disclosure relates to an imaging unit and an endoscope apparatus, the imaging unit being provided at a distal end of an insertion unit of an endoscope that is configured to be inserted into a subject to image the inside of the subject.
2. Related Art
Endoscope apparatuses have been widely used to perform various examinations in a medical field and an industrial field. Among those apparatuses, a medical endoscope apparatus is widely used because an in-vivo image of a body cavity can be acquired without making an incision on a subject such as a patient by inserting an elongated, flexible insertion unit provided with an image sensor at a distal end thereof into the body cavity of the subject and, at the same time, a curative treatment can be performed as needed by projecting a treatment tool from the distal end of the insertion unit.
Fitted to the distal end of the insertion unit of such endoscope apparatus is an imaging unit including a solid state image sensor and a flexible printed circuit board (hereinafter referred to as an FPC board) employing Tape Automated Bonding (TAB) or the like and populated with electronic components such as a capacitor and an IC chip constituting a drive circuit of the solid state image sensor, where a signal cable is soldered to the FPC board of the imaging unit. An inner lead exposed from an end face of the FPC board is bent along a side of a light-receiving surface of the solid state image sensor from a side face thereof, and is connected to an electrode pad formed in the solid state image sensor.
As a technique of connecting the inner lead and the electrode pad, there is disclosed a technique in which an insulating carrier tape material of an FPC board is arranged on the side of a solid state image sensor, the FPC board being formed of the carrier tape material and a wiring layer including an inner lead formed from metal foil such as copper foil adhering to the carrier tape material (refer to Japanese Patent Application Publication No. 2001-257937, for example). Japanese Patent Application Publication No. 2001-257937 also discloses a technique in which the inner lead extending from a wiring pattern on the back side of a base material (back side of a surface on which an electronic component is mounted) of the FPC board is connected to the electrode pad of the solid state image sensor, the FPC board including the wiring pattern formed on both sides of the base material.